Durable and sustained immune tolerance to ERT in Pompe disease with entrenched immune responses.

BACKGROUND: Enzyme replacement therapy (ERT) has prolonged survival and improved clinical outcomes in patients with infantile Pompe disease (IPD), a rapidly progressive neuromuscular disorder. Yet marked interindividual variability in response to ERT, primarily attributable to the development of antibodies to ERT, remains an ongoing challenge. Immune tolerance to ongoing ERT has yet to be described in the setting of an entrenched immune response. METHODS: Three infantile Pompe patients who developed high and sustained rhGAA IgG antibody titers (HSAT) and received a bortezomib-based immune tolerance induction (ITI) regimen were included in the study and were followed longitudinally to monitor the long-term safety and efficacy. A trial to taper the ITI protocol was attempted to monitor if true immune tolerance was achieved. RESULTS: Bortezomib-based ITI protocol was safely tolerated and led to a significant decline in rhGAA antibody titers with concomitant sustained clinical improvement. Two of the 3 IPD patients were successfully weaned off all ITI protocol medications and continue to maintain low/no antibody titers. ITI protocol was significantly tapered in the third IPD patient. B cell recovery was observed in all 3 IPD patients. CONCLUSION: This is the first report to our knowledge on successful induction of long-term immune tolerance in patients with IPD and HSAT refractory to agents such as cyclophosphamide, rituximab, and methotrexate, based on an approach using the proteasome inhibitor bortezomib. As immune responses limit the efficacy and cost-effectiveness of therapy for many conditions, proteasome inhibitors may have new therapeutic applications. FUNDING: This research was supported by a grant from the Genzyme Corporation, a Sanofi Company (Cambridge, Massachusetts, USA), and in part by the Lysosomal Disease Network, a part of NIH Rare Diseases Clinical Research Network (RDCRN).

Bortezomib in the rapid reduction of high sustained antibody titers in disorders treated with therapeutic protein: lessons learned from Pompe disease.

PURPOSE: High sustained antibody titers complicate many disorders treated with a therapeutic protein, including those treated with enzyme replacement therapy, such as Pompe disease. Although enzyme replacement therapy with alglucosidase alfa (Myozyme) in Pompe disease has improved the prognosis of this otherwise lethal disorder, patients who develop high sustained antibody titers to alglucosidase alfa enter a prolonged phase of clinical decline resulting in death despite continued enzyme replacement therapy. Clinically effective immune-tolerance induction strategies have yet to be described in the setting of an entrenched immune response characterized by high sustained antibody titers, wherein antibody-producing plasma cells play an especially prominent role. METHODS: We treated three patients with infantile Pompe disease experiencing marked clinical decline due to high sustained antibody titers. To target the plasma cell source of high sustained antibody titers, a regimen based on bortezomib (Velcade) was used in combination with rituximab, methotrexate, and intravenous immunoglobulin. RESULTS: The treatment regimen was well tolerated, with no obvious side effects. Patient 1 had a 2,048-fold, and patients 2 and 3 each had a 64-fold, reduction in anti-alglucosidase alfa antibody titer, with concomitant sustained clinical improvement. CONCLUSION: The addition of bortezomib to immunomodulatory regimens is an effective and safe treatment strategy in infantile Pompe disease, with potentially broader clinical implications.

Co-occurrence of Chiari malformations and sickle cell disease-a diagnostic dilemma: a report of 4 cases and review of literature.

The co-occurrence of sickle cell disease (SCD) and Chiari malformation (CM) poses clinical and diagnostic challenge since symptoms of both conditions may overlap. Although SCD and CM do not have a causal relationship, the overlapping neurologic symptoms may pose a diagnostic dilemma. To the best of our knowledge, the clinical manifestations and long-term consequence of CM in children with SCD has hitherto not been reported in the literature. We describe clinical manifestations of co-occurrence of SCD and CM in a case series of 4 African American children.

6-year-old girl with hydrocephalus.

With rare exceptions, pediatric tectal gliomas have been generally reported as low-grade tumors with relatively good prognosis. The patients are usually treated conservatively to manage the signs and symptoms of obstructive hydrocephalus. We report a case of a tectal glioma in a 6-years-old girl with histological features of anaplastic mixed oligoastrocytoma that continues to progress despite chemotherapy and radiation therapy.

Student evaluation practices in pediatric clerkships: a survey of the medical schools in the United States and Canada.

Despite the curriculum changes during the past decade, there is paucity of information regarding the structure and evaluation processes in pediatric clerkships. Information regarding the educational components of the pediatric clerkship and student evaluation practices was obtained from the pediatric clerkship directors via a paper/electronic survey. Completed surveys were received from 97 US and Canadian medical schools and were analyzed. The average length of a clerkship was 7 weeks. Most clerkships required a 4-week ward, a 1-week newborn rotation, and a 2-week ambulatory rotation. Students were evaluated on each component of the clerkship in 93.5% of the programs. All programs evaluated student's clinical performance and fund of knowledge; 85.6% evaluated student's written record. Student's clinical performance was evaluated by direct observation in 57% of the programs. Penalties for failing in clinical performance were harsher. In 56% of programs, a student failing in clinical performance failed the entire clerkship in contrast to 21.8% or 7% of the programs where a student failed the entire clerkship if they failed in the examination for the fund of knowledge or written record evaluation, respectively. The survey demonstrated a fair amount of consistency in clerkships across programs when compared with data obtained in 1981 and 1986. There was a noticeable increase in the well-baby nursery rotation; however, there was a decline in direct observation to assess physical examination or clinical performance.

Severe intrarenal fibrosis, infundibular stenosis, renal cysts, and persistent perilobar nephrogenic rests in a patient with Beckwith-Wiedemann syndrome 27 years after diffuse nephroblastomatosis and Wilms tumor: natural progression or a consequence of treatment?

A27-year-old woman presented with back and abdominal pain. She was diagnosed in infancy with Beckwith-Wiedemann syndrome and bilateral multifocal perilobar nephrogenic rests that progressed to diffuse nephroblastomatosis with neoplastic nephroblastomatous rests at 14 months of age and subsequently to a right Wilms tumor at 5 years of age. Computed tomography of the abdomen during the current admission showed multiple obstructed calices. Ureteroscopic inspection of the left kidney revealed severe intrarenal scarring with multiple infundibular stenosis, hydrocalices, and nephrocalcinosis. Renal biopsy showed sclerotic glomeruli with calcification and scarring and persistent subcapsular nodular renal blastema. Electrocautery incision and balloon dilatation provided temporary pain relief. After discharge, the patient has had two or three episodes of recurrent pain associated with new areas of infundibular stenoses and renal cysts. Bilateral nephrectomy and renal transplantation is being considered for management of progressive disease and relief of intractable pain. The potential causes of progressive and severe intrarenal fibrosis, infundibular stenosis and nephrocalcinosis, and renal cysts in this patient may include abnormal renal development secondary to Beckwith-Wiedemann syndrome itself, radiation or chemotherapy damage, or a combination.